the fbi traced those e-mails to petraeus' biographer paula broadwell. and in the process discovered she and petraeus had had an affair. a former spokesman for petraeus said this of the relationship. >> the affair started approximately two months after he was in the cia and ended about four months ago. >> reporter: according to officials, the fbi didn't report the incident to petraeus' boss or congress or the president. until concluding its investigation last week. the president accepted petraeus' resignation friday. >> it's very puzzling. and i think was a mistake, because this thing just came so fast and so hard, and since then it's been like peeling an onion. >> reporter: roger is defending the fbi. >> but once the fbi concluded there was no national security breach by the cia director, there was really nothing there. >> reporter: he said he's more concerned about what happens next. as congress investigates the attack in benghazi, libya, as with now without testimony from petraeus. acting cia director mike morerel will testify in petraeus' place this